Semiconductor device including analog to digital conversion circuit
AssigneeRenesas Electronics Corporation
InventorsMasaaki Usui, Shunsuke Nakano
Life of this patent
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Abstract
An object of the present invention is to shorten time required for detecting disconnection in an input terminal of an A/D conversion circuit. A semiconductor device includes a first input channel that couples a first input terminal and an A/D conversion unit to each other, a second input channel that couples a second input terminal and the A/D conversion unit to each other, and a control circuit unit that separates the second input channel from the second input terminal and the A/D conversion unit to charge or discharge the second input channel when a signal input into the first input terminal is sampled by the A/D conversion unit.
Claims18
A semiconductor device comprising:
- a first input terminal;
- a second input terminal;
- an A/D conversion unit having a sample hold circuit;
- a first input channel that couples the first input terminal and the A/D conversion unit to each other;
- a second input channel that couples the second input terminal and the A/D conversion unit to each other;
- and
- a control unit that provides:
- in a first period, a first set of signals to enable electrical connection between the first input terminal and the A/D conversion unit through the first input channel, such that a signal input into the first input terminal is sampled by the sample hold circuit,
- in a second period, a second set of signals to disenable electrical connection between the second input terminal and the A/D conversion unit through the second input channel, and
- in a third period, a third set of signals to enable charging or discharging of the second input channel,
- wherein a portion of the first period, a portion of the second period, and a portion of the third period overlap with each other.
A semiconductor device comprising:
- a first input tell terminal;
- a first input signal selection switch that is coupled to the first input terminal;
- a first input signal line that is coupled to the first input signal selection switch;
- an input unit that is coupled to the first input signal line;
- an output signal line that is coupled to the input unit;
- and
- an A/D conversion unit that is coupled to the output signal line,
- wherein the input unit includes:
- a first parasitic capacitor that is coupled to the first input signal line;
- a first charge control switch that couples a power supply line to the first input signal line;
- a first discharge control switch that couples a grounding wire to the first input signal line;
- a first switch that couples the output signal line to the first input signal line;
- a common parasitic capacitance capacitor that is coupled to the output signal line;
- a charge switch that couples the power supply line to the output signal line;
- and
- a discharge switch that couples the grounding wire to the output signal line.
Dependencies are inferred from the claim text.